I installed GoLabel and used a sample to see how it works. From what I see when I press the Import option, the software will add the barcode on the file based on the commands given. Therefore, you have to know how to implement those barcodes into the Command Line, and then you can import them into the design area. You can have as many as the design area allows.
To read about Excel database, access the built-in Help file using other GoLabel Online Help (ignore the Online word because it opens from a local source).